Piston ring



C. L. POST PISTON RING Jan. 4, 1927.

2 Sheets-Sheet `l I fo 1,613,410 Jan 4 1927 c. L.. PosT PISTON RING Filed oct. 14, 1922 2 sheets-Sheet 2 inventor PATENT j OFFICE.

CLAUDE POST, OF PHILADELPHIA., PENNSYLVAIA.

rIs'roN nrNG.

Application led October 14, 1922.v Serial No. 594,461.

4 sive and 'other engines and having a con- .ring with a varying width of contact against struction especially adapted for insuring immediate accurate fitting of the cylinder bore and further provided about its perimeter adjacent to the bottom end with a groove adapted for controlling the degree of'elasticity of the ring circumferentially and radially considered, and also providing reserl voir space for receiving the oil required for the lubrication during the reciprocation of the piston.

My inventionmore specifically comprises an expansible one-piece split piston ring having the greatest cross sectional area' arranged immediately adjacent to the split or toe ends and also in that portion or heel of the ring diametrically opposite the said split portion, and the cross section reduced intermediate of the said parts by a grooved outer perimeter open to one edge of the ring and so shaped as to give to the ring a gradual varying cross sectional area between the toe portions and the heel portion, said varying cross sectional area preferably decreasin gradually along the sides' from the toe en s and the body or .heel of the ring diametrically opposite and having the smallest cross sectional area nearer to the toe'ends than to the heel portion of the ring diametrically opposite. i

The invention further comprises the foregoing construction wherein the grooved reservoir portions at each side of the ring between the portions of greatest cross sectlonal area are united by avery shallow groove in the heel portion to permit oil topass circumferentially from one reservoir groove to the other and vice versa, to equalize the oil supply.

My invention further comprises a split one-piece expansible piston ring having its perimeter turned with a series of exceeding ly lfine' grooves forming slight circumferential ridges, said ring being turned when `fully compressed, whereby it is'accurately of circular construction in its operative condition and presents exceedingly 'fine ridges about its circumference which permit the ring to seat itself quickly and accurately assume a condition of perfectly fitting the bore of the cylinder when the same is slightly out of round.

My object is furtherl to provide the piston the cylinder wall, whereby the greatest possible bearing surface is provided where the greatest wear occurs and said surface tapering offto the least bearing surface where the least wear occurs, thereby giving to the ring the combined advantages of 'both the eccentric and concentric types of rin My object 4is further to provide a split ring with its ends rabbeted to provide overlapping projections on the step portions oneof which overlapping portions is slight-l ly longer than the other, whereby it becomes necessary to file only the end of one of these step portions to enablethe ring to accurately lit the cylinder bore without a material gap and .permitting the'fitting to be accomplished in a speedy and easy'manner.

With the above and other objects in view, the nature of which will be more fully understood from the description hereinafter, l

looking at the side where it is split; Fig. 4 5

is a' similar view looking at the side diametrically opposite to the split; Fig. 5 is a similar view of the ring from the position at right angles to the position shown in Figs. 3 and 4; Figs. 6, 7, 8, 9 and 10 are cross sections taken respectively on the dotted lines 6 6, 7-7, v8-8, 9-9 and 10-10' of Fig. 2; Fig.11 is an inverted plan view, corresponding to Fig. 2, of my improved piston ring showing the groove variable in depth in a radial direction; Figs. 12, 13, 14, 15 and 16 are cross sections of the same taken respectively on dotted lines 12-12, 13-13, 14-14, 15-15 and 16-16 of Fig.

11; Fig. 17 is an elevation of the middle I portion of Fig. 3, when the piston ring is compressed to close the gap; Figs. 18 and 19 are perspective views of my improved piston ring; andFigs. 20 and -21 are cross sections illustrating modifications.

.2 is the bodl of the rin and normally, as shown in the rawin s, it y1s of greater diameter than that whic Ait assumes when in operation in the cylinder. A portion of this ring `is cut away to form a. split and gap in its circumference and roviding thereat free or toe ends 3, 3, whic are so shaped asto have rabbets 4- and 5 presenting projecting loo portions 6 and 7, respectively. When the ring is compressed, these projecting portions 6 and 7 overlap each other in close juxtaposition, as indicated in Fig. 17 and, moreover, the lengths of these parts 6 and 7 are different so that one of them. as'6 alone, contacts with the rabbeted portion of the other ring end, as will be clearly understood from Fig. 17, wherein the pants 5 and 6 are in close contact while there is provided between the parts 4 and 7 a slight space or gap, By malrmg the projecting portions 6 and 7 of different lengths, it then onlv becomes necessary in fitting the ring to the pistonto ile one of the projecting portions alone and thereby save time and labor.

When the ring is compressed to approximately the working diameter, it is then turned in a lathe so as to have its peripheral Surface formed as a true circleand, moreover, the peripheral surface is turned with a series of exceedingly fine grooves presenting radial projecting circumferential ribs 8 Figs. 6 to 10, inclusive) to enable the ring to seat itself quicklv to a cylinder that. is slightly out of round.

As shown in the drawings, the heel portion S has a vertical bearing surface of approximately the full height of the ring and, similarlv, the toe portions 3. have full vertical bearing surfaces 8, these portions being those which experience has shown receives the greatest amount of wear. Between the heel and toe portions on each side Lof the ring, the metal at the lower portion 9a is cut away to form a groove 9, saidgroove extending to the bottom of the ring .and bounded at the upper portion by a shoulder 9", the said shouldered portion being arranged circumferentially along its length at dii'erent distances from the bottom of the ring so -that the groove is ot variable vertical height. and by reason thereof, forming the circumferential bearing surface of the ring of variable vertical height, said height being inversely proportional to the vertical vheight of the groove. As shown, the greatest vertical height of the groove and the minimum height of the bearing surface occurs at a position 9-9 of the grooved portion between 8" and 9EL which is preferably approximately 60 from the toe ends or split vportion of the ring and from this position the said shouldered portion 9b of the groove slopes gradually downward toward the toe ends and toward the heel portion of the ring, as will be readily7 understood from reference to Figs. 3, 4 and 5. This construction gives a variable cross sectional area along the sides ofthe ring from the heel to the toe ends.y A number of cross sections aboutgthe ring, taken at the lines 6-6, 7 7, 8--8, 9-9 and 10-10, are shown respectively in Figs. 6 to 10, inclusive.v

From Fig. 9, it will be seen that the cross sectional area of the ring is a minimum and radial flexibility to permit the ring to as sume the cylindrical shape when compressed to a smaller diameter with all the advantages of the eccentrically bored type, of ring, so that this atvantage is secured with the additional adv ntage of providing the toe portion with a gradually increasing cross sectional area to provide the necessary bearing and at the same time permit the'proper cooperation of the said toe ends to close the :gap in the ring and without excessive wear at this portion.

` Referring now to Figs. 11 to 16, inclusive, the piston ring is, in general, formed the same as in the construction illustrated in Figs. 1 to 10, inclusive, but in which further the radial depthv of the groove 9 is varied so that the inner wall bounding the groove is of least radial thickness adjacent to the vheel portion 8 and toe portions 3, 3, and of greatest radial depth approximately'at 9a, preferably in this case about 30 from the split be-.

tween the toe ends, and corresponding to the place of least contact of the outer peripheral bearing surface of the ring. The cross sectional area shown in Fig. 15 of the ring shown in Fig. 11 corresponds to the cross sectional area of Fig. 9 of the ring shown in Figs. 1 and 2, with the exception that the radialdepth of the groove 9 is greater in the case of Fig. 15 than in the case of Fig. 9. The result of this isthat greater flexibility is provided for equal sizes of the ring, but it also provides capacity for maintaining equal flexibilities 'with an increased peripheral bearing surface. For more convenient comparison, it is pointed out that Figs. 11 to 16 correspond to Figs. 2, 6, 7, 8',` 9 and 10, except as to the variable radial depth of the groove 9 in the former, the cross sections of the ringy in Figs. 12 to 16, inclusive, corresponding in positions to the cross sections of Figs. 6 to 10.

In thevnse of my improved ring, the edges 9, 9b and 9, constituteoil scraping edges for collecting the oilon the suction stroke and carry it to the lowest point of the ring travel deposit or distributing. the oil against the cylinder Wall on the next upward stroke, the capacity of the reservoirs formed by the grooves r9, being sufiicient to hold all the oil required-for this purpose. llt will also be lllO understood that the varying depth of the outer circumferential portion of the Ting, taken in connection with the 'turned fine rigged faces, enables a quick seating of the ring to the shape of the cylinder bore, and the provision of the full vertical face of the ring at the heel and toe portions insures long life and efficiency. This improved ring in providing a varyin Width of contactv againstl the cylinder wa gives itthe greatest possible bearing where the greatest wear oc curs and tapering olf in its area of contact to the least bearing where the least Wear arises, thereby givingl to the ring the combined advantages vof both the eccentric and .the concentric types of rings. l l

While I have described my invention in considerable exactitude in respect to the more preferred construction, particularly with respect to the shape of the grooves, I desire to state, however that I do not confine myself to the groove which is formed Wi'h abrupt vor right angled walls, as the groove or the part l constituting the equivalent thereof when the ring is in use may be of various shapes in cross section such, for example, as shownin Figs. 20 and 21, from which it will be seen that in Fig. 20, the groove is formed of a curved wall 9i instead of the right angled walls indicated in Figs. 6 to 9, inclusive. Similarly, in Fig. 21, the bevel 9 provides the undercut portion constituting the groove. In this figure I have indicated the piston 12 with a groove 11 for the piston ring. In practice, there would be a numberk of rings used in connection with a single piston, and these rings `may be all applied with their grooves-directed to one end of the piston or part directed to. one end and to the other end, as preferred.

It will also be understood that, if desired,- part of the rings may have the moreabrupt shouldered grooves of Figs. 7 to 9 and 13 to part 15, inclusive, providing a maximum space within the outer confines ofthe piston to constitute oil grooves, nevertheless, the modied form of Figs. 20 and 21 provide oil spaces in the piston grooves which are amply suicient in some cases and especially where the said rings are employed in association with the rings having the more abrupt grooves. It will be understood, therefore, that when I refer t o"grooves in connection with the' ring either in the specification or claims, I -am employing theY said term in a relatively broad sense to include all the possible variations in the grooved portions such as illustrated in various figures of the drayvf ings, including Figs. 20 and 21.

It will now be apparent `that I have devised a novel and useful construction which embodies the features of advantage enumerated as desirable, and while I have in the present instance shown and described the preferred embodiment thereof which has been found in practice to give satisfactory and'reliable results, it is to be'understood that I do not restrict myself to the details, as the same are susceptible of modification in various particulars without 'departing from the spirit or scope of the invention.

Having now described my invention, `what I 'claim asnevv and desire to` 'secure by -Letters Patent is I f 1. A one-piece split expansible piston ring having .an outer maximum bearing surface adjacent to the split ends and on the body diametrically opposite thereto, and having further the circumferential `portions of the ring intermediate of the said maximum bearing surface portions with a grooved construction Whlerein the. groove extends to the perimeter and also to the end face of the ring to remove the main portion at one annular corner and lsaid grooved construction comprising two grooves extendingr respectively between the maximum bearing surfaces and on diametrically opposite portions of the ring, said grooves'having gradual decreasing cross sections in the direction from thesplit en.l`of the ring toward the maximum bearing\surface diametrically opposite thereto.

. 2. A one-piece'split expansible piston ring having an outer maximum bearing surface adjacent to the -split ends and on the body diametrically opposite thereto, and having further the circumferential portions of the ring intermediate of the said maximum bearing surface portions with a grooved construction giving to the ring a variable cross section at different positions circumferentially considered, the circumferential portions intermediate of the maximum bearing surfaces gradually decreasing in area and with the, minimum surface positioned approximately from wthe split ends.

3. The invention according to claim 1, wherein, further, the grooved portions at each vside of the split portion of the ring are connected by. an exceedingly small groove, adjacent tothe body of the maximum bearing diametrically opposite to the split portion of the ring, whereby'oil may pass from either grooved portion of the ring to the otier for equalizin'g the distributionv of the o1 ff 4. The invention according to claim 1,

aol

wherein further, the grooves radially con-l sidered increase in depth from the part diametrically opposite to the` s lit ends and in. .directions toward said sp it ends, the

depth beinggreatest at places nearer to the.

wherein further, the body portion of the ring diametrically opposite from the split part thereof is provided with a very shallow and small groove connecting the reservoir grooves on opposite sides of the ring and lel shallow grooves which furnish exceedingly small projecting parts adapted to quickly Wear down to a true it to the cylinder While at the same time maintaining a substantially continuousgeneral perimeter to the ring.

8. The invention according to claim 1, wherein further, the grooves arel formed of a radial variation in depth between the portions of greatest bearing surface, the greatest depth of the grooves being nearer to the split ends of the ring than to the portion of .the ring diametrically opposite thereto.

9. rJlhe invention according to claim l, wherein further, the grooves formed in the perimeter of the ring are of variable depth in a radial direction at dierent places circumferentially considered, and in which the greatestradial depth of the grooves are ad- 'acent to those portions of the peripheral earing surface presenting the minimum bearin surface.

l0. ring having an outermaximum bearing surface adjacent to the split ends and on the 40 body diametrically opposite thereto, and having further circumferential portions of one-piecev split expansible piston i the ring intermediate of the 'said maximum bearing portions formed of a constructlon giving to the ring a variable cross section at diierent portions circumferentially con--v sidered, the circumferential portions intermediate ofthe maximum bearing surfaces being provided with gradually decreasing 4 bearing surfaces and with the minimum surface at a distance fromv the split ends of the ring.

ln testimony of which invention, li hereunto set. my hand.

@Linnen roer. 

